MONDAY, June 3 (HealthDay News) -- In an attempt to better understand the genetics of breast cancer, new research suggests that about 20 percent of black women with the disease have an abnormality on at least one of 18 genes previously linked to breast cancer vulnerability.

And those women with either aggressive "triple negative" breast cancer, early onset disease or a family history of breast and ovarian cancer are most likely to have such genetic abnormalities, the study authors said.

The finding might one day lead to improved risk screening for the disease, the researchers said.

"For many years, we've seen breast cancer take a heavy toll on African-American women, and this study begins to resolve unanswered questions about what's driving these disparities," study lead author Dr. Jane Churpek said in a news release from the University of Chicago, where she is an assistant professor of medicine.

"While larger studies are needed to confirm our results and compare them to other populations, we hope our findings will lead to increased awareness about potentially life-saving genetic screening for African-American women with a personal or family history of early onset or aggressive forms of breast cancer and their relatives," she said.

Churpek and her colleagues are scheduled to present their findings Monday at the American Society of Clinical Oncology (ASCO) annual meeting, in Chicago. Research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.

The result: 22 percent of the women had at least one gene abnormality, with most carrying just a single mutation.

The researchers said the women in the study were selected from those referred to the University of Chicago for genetic counseling, so they had a greater risk of a genetic mutation than the general population of black women. Still, the researchers said, they were surprised at the rate of mutations because only 5 percent to 10 percent of all breast cancer cases are thought to have a genetic cause.

Dr. Andrew Seidman, an ASCO spokesman, said in the news release that the study findings indicate the need for increased genetic screening, especially since black women are known to face a relatively high risk for aggressive triple negative breast cancer and often have poorer survival rates.

"These results argue for increased screening for mutations in African-American women diagnosed with breast cancer at a younger age, [women diagnosed] with triple negative breast cancer or women with a family history [of breast cancer]," he said. "Since such testing may lead to life-saving interventions for their family members, these data underscore the need to overcome barriers to genetic testing for breast cancer risk among African-American women."

The research was funded by the U.S. National Institutes of Health, the Breast Cancer Research Foundation and Komen for the Cure.